Conversion of hydrocarbons



Patented Feb. 12, 1946 CONVERSION OF HYDROCARBONS Richmond T. Bell,Highland Park, Hillis 0. Folkins, Skokie, and Carlisle M. Thacker,Highland Park, 111., assignors to The Pure Oil Company, Chicago, Ill., acorporation of Ohio No Drawing. Application February 12, 1944, SerialNo. 522,086

14 Claims.

This application is a continuation-in-part of application Serial No.482,608, now Patent No.

v 2,374,167, and relates to conversion of hydrocarbons to lower boilinghydrocarbons or to the conversion of hydrocarbons into hydrocarbonscontaining less hydrogen in the molecule,

One of the objects of the invention is to provide an improved method forconverting hydrocarbons into lower boiling hydrocarbons.

Another object of the invention is to provide catalysts or sensitizerswhich can be used in conventional types of cracking processes toaccelerate the rate of cracking or to make possible cracking ofhydrocarbons at lower temperatures.

Other objects of the invention will become apparent from the followingdetailed description.

In accordance with our invention, the hydrocarbon to be converted ispassed through a reaction zone together with a small amount of analiphatic organic compound containing a member of the halogen group ofelements and a member of the oxygen family. We have found that aliphatichydrocarbons containing both halogen and oxygen, sulfur, selenium ortellurium substituted in the molecuule have a marked effect inaccelerating cracking of hydrocarbon oils and gases into lower boilinghydrocarbons and into more unsaturated hydrocarbons. Halogenatedderivatives of the following general groups of compounds are effective;alcohols, aldehydes, acids, ethers, ketones, esters and epoxy compounds.Epoxy compounds are those having an oxygen atom bonded to differentradicals already united in some other way. The halogen may besubstituted for hydrogen in one or more alkyl or other radicals. Forpurposes of brevity the term oxy-halogenated will hereinafter be used tomean compounds containing halogen and one or more members of the oxygenfamily, viz., oxygen, sulfur, selenium, telluriumr As specific examplesof compounds which we "have found will accelerate the cracking ofhydrocarbons are ethylene bromohydrin, ethylene chlorohydrin, chloral,dichloracetylchloride, chloromethyl ether, eth l chloracetate and theepoxy compounds, epichlo ohydrin an'd epibromohydrin.

In carrying out our invention, the hydrocarbons undergoing reactionshould contain in admixture therewith from 0.1 to mole percent of theoxy-halogenated aliphatic compound, although we prefer to use from .25to 3 .mole percent. Higher or lower amounts'of sensitizer may be usedbut within the range above specified the increase in reaction rate isvery marked and formation of undesirable amounts of halogen and/oroxygen reaction products is avoided.

Although oxy-halogenated compounds in which chlorine is substituted foran element or radical in the molecule are effective, we have found thatbromine-substitutedcompounds are much more effective than chlorinesubstituted compounds. For example, epibromohydrin appears to beapproximately ten times as effective as epichlorohydrin when used inamounts of 1 mole percent. 5 Our invention may be carried out inconventional cracking apparatus either of the straight thermal orcatalytic type, The sensitizer may be mixed with the hydrocarbon oil,vapor or gas undergoing conversion prior to charging it to the reactionzone, or the sensitizer may be injected directly into the reaction zone.Although we prefer to use sensitizers which are in the same physicalstate as the hydrocarbons at reaction temperature, compounds may be usedwhich exist 16 i a different physical state from the hydrocarbons atreaction temperature. The sensitizer, if

soluble in the hydrocarbonsundergoing conversion, may be dissolvedtherein prior to passage through the reaction zone, or may be dissolved20 in a small portion of the hydrocarbons undergoing reaction and fedinto the main stream of hydrocarbons in desired proportions. If thesensitizer is insoluble in the hydrocarbon undergoing reaction, a slurryof the sensitizer in a portion of the hydrocarbon oil may be preparedand fed in desirable proportion into the main-stream of oil. Where it isdesired to crack gases or oil in vapor phase, a sensitizer is preferablyselected which vaporizes readily and can be mixed with the vaporsundergoing conversion. We prefer to introduce the sensitizer into themixture undergoing reaction in such manner that decomposition of thesensitizer does not occur until it is in contact with the hydrocarbonsundergoing de- 5 composition at reaction temperature. One

method of doing this is to flash inject the sensitizer into the reactionchamber without appreciably preheating it.

Cracking with sensitizers in accordance with our invention may becarried out under subatmospheric, atmospheric or superatmosphericpressure and at temperatures from the lowest temperatures at whichcracking will occur to temperatures of approximately 2000 F., dependingupon the type of product it is desired to produce. Where cracking ofhydrocarbon'oil is conducted for the purpose of making lighter oil,-suchas gasoline, temperatures ranging from approximat-ely 650 to 1200 F. maybe used. Where cracking of hydrocarbon oils or gases for the purpose ofmaking aromatic hydrocarbons is practiced, temperatures of approximately1000 to 1500 F. may be used. Where it is desired to produce butadienefrom hydrocarbon oils, temperatures from the vicinity of 1300 to 1600 F.may

be used,.and where it is desired to crack hydrocarbon oils to gases,hydrocarbon temperatures of from approximately 1200" to 2000 F. may beused.

In order to demonstrate the invention, a series ing stock. The runs wereall made at a temperature of 525 C. in laboratory apparatus constructedPyrex glass. Before each run, the reaction vessel was evacuated to 0.001mm. or less of mercury while maintaining the temperature at the desiredreaction level. Normal butane admixed with the desired amount orsensitizer was then charged to the reaction chamber until the pressuretherein was approximately atmospheric pressure. Pressure increases inthe reaction chamber were noted at definite intervals ranging from 0.5to 2 minutes until a pressure increase of 25% had been attained. At thetime the pressure increase reached 25%, the reaction chamber was quicklyevacuated and the reaction products were analyzed for carbon dioxide oracidic constituents by absorption in caustic potash solution, forunsaturates by absorption in fuming sulfuric acid, for hydrogen bycontraca of runs was made using normal butane as chargsensitizer. Thesensitizationfactor is therefore a true indication of the rate ofacceleration of the reaction caused by the sensitizer. In determiningsensitization factors the average figures for the blank runs immediatelypreceding a sensitized, run in the table were used as a basis forcomparison. As is apparent from the table, although both epichlorohydrinand epibromohydrin sensitized cracking reaction to a marked extent,

epibromohydrin is far superior to epichlorohy- I drin. With 1 molepercent of epibromohydrin in the reaction mixture the reaction rate wasincreased almost 2400 percent.

The reaction products formed in the runs regardless of whethersensitizer is present or not present are fairly uniform and as indicatedby the large amount of unsaturates formed and the low amount ofhydrogen, the reaction is primarily one of splitting of the carbon tocarbon bond. The larger amount of unsaturates formed in runs Thesensitization factor for pressure changes of 5%, 12.5% and pressureincrease is obtained by dividing the time required for the particularpressure increase without sensitizer by the o in volume due to water f mn, and for 1034-1". and 1035-1. is due to the fact that these carbonmonoxide by oxidation followed by abruns were carried to point in excessof 2 sorption in caustic potash solution. t pre'ssure increase,

In certain runs indicated in the followin Our invention is applicable toimprovement of table, e pressure rose o a P011117 above 25 25 varioustypes of thermal cracking operation now p ent p e increase before the us in commercial use 11 which no catalyst is used mmated- In these runsthe time required for a and also to improvement of catalytic cracking 2Pressure increase was interpolated from 8 processes of known commercialtypes. It is poscurve based on time and pressure observed dursible toimprove presentcommercial cracking op- 1 ing the run. erations withoutthe necessity of changing the In a i ion o h r n m e h epichloroprocessand apparatus except to make provision hydrin and epibromohydrin assensitizer, a numtoigcharglng a. small amount of sensitizer to the beroi blank runs were made in which only noroperation,

7 mal butane without sensitizer was charged to the In t l i s th groupreaction vessel.

I The following table contains in tabulated form I on I the resultsobserved on the various runs.

' Table in 1001' Y Sensitizationlactor mum I g m T l for APOP Molepercent reaction products Run N0. pre cm.

' Names 33 0 12.5 20% 0% 2.5% 25% Acids Unsat. oo 11. Residue Avz----1aa0 mm- 1.20 0.11 18.63 0.0 220 0.1 1.0 103 1010-1 00.40Epichlorohydrim- 1.0 0.33 1.00 1.00 3.0 0.1 2.0 0.0 21.0 0.1 1.1 11.0

Avg-...- 01.10 None. 2.30 an 21.44 0.0 21.0 0.2 1.1 14.0 mm-r 01.00Epichlorohydrin" 1.0 0.00 1.30 3.10 0.1 0.0 24 0.0 220 0.2 1.2 10.01021-2 01.00 Epichlorohydrim- 0.0 0.00 I 0.22 10.01 0.0 as 1.0 0.0 23.00.1 1.2 10.1 1024-1 01.00 Epichlorohydrin.- 0.111 1.00 0.04 11.00 2.01.4 1.2 0.0 21.0 0.1 1.4 110 1021-1 mas-r 1030-2 1011 vg 80.05 None 1.787.08 19.70 0.1 21.7 0.1 1.8 76.3 1034-1 111.00 Epibromohydrim- 1.0 0.130.32 0.83 11.1 22.0 22.1 0.0 20.1 0.0 00 11.0 1000-11 10.10Epibromohydrm- 00 0.10 0 40 1.11 0.0 10.0 11.0 02 24.2 0.0 1.0 10.41000-11 80.00 Epibtomohydrlm. 0.20 0.24 0.11 \00 1.4 0.0 0.0 0.1 220 000.0 10.0

1 Run carried to pressure increase. Run carried to 20% pressureincrease.

is the radical resulting from the removal '01 one hydrogen atom fromepoxyethane.

We claim: 1. The method of cracking hydrocarbons which time required forthe same pressure increase with comprise subjecting said hydrocarbons tosuitable cracking conditions of time, temperature to temperaturesbetween 650 and 2000 F. in the and pressure in the presence of a smallamount presence or about 0.1 to 3 mole percent of epiof a halogenatedepoxy compound. to bromohydrin. '7

2. Method according to claim 1 in which the 10. The method of cracking p-conta halogenated epoxy compound contains the group 5 ing as for theproduction of ethylene which comprises subjecting said gas to crackingtempera- CH I tures in the presence of a small amount of a halogenatedepoxy compound containing the in the molecule. group 3. Method inaccordance with claim 1 in which the halogenated epoxy compound isepibromohydrin. OH, H

4. Method in accordance with claim 1 in whic the halogenated epoxycompound is epichloro- Method in accordance with claim 10 in hydrm Whlchthe halogenated epoxy compound is pi- 5. The method of crackinghydrocarbons which bromohydrm and it is present in amounts fromcomprises subjecting said hydrocarbons to temo'lt'oamolepercentperatures of 650 to 2000 F. in the presence of '.rhe method ofhydrocarbon oil f m approximately to 3 mole percent of a comprisingcontacting said 011 with a small halogenated epoxy compound amount ofepibromohydrin at temperatures of 6. Method in accordance with claim 5in which to for Sumcient to Obtain a e the epoxy compound contains therou stantial yield of hydrocarbon of gasoline boiling range. a W 13.Method in accordance with claim 12 in which the epibromohydrin ispresent in amounts I in the molecule. of approximately 0.1 to 3.0 molepercent of the '7. Method in accordance with claim 5 in whichhydrocarbon oil. the halogenated epoxy compound is epibromo- 14. Methodin accordance with claim9inwhlch hydrin. the hydrocarbon is butane, thetemperature is ap- 8. Method in accordance with claim 5 in whichproximately 977 F. and the epibromohydrin is the halogenated epoxycompound is epichloropresent in an'amount of 1 mole percent. hydrin.

9. Method of cracking hydrocarbons contain- RICHMOND T. BELL. ing atleast three carbon atoms per molecule HILLIS O. FOLKINS. which consistsin subjecting said hydrocarbons CARLJSLE M. THACKER.

